Diapause induction and overwintering stage in the fir coneworm (Lepidoptera : Pyralidae)

Citation
R. Trudel et al., Diapause induction and overwintering stage in the fir coneworm (Lepidoptera : Pyralidae), CAN ENTOMOL, 131(6), 1999, pp. 779-786
Citations number
29
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Entomology/Pest Control
Journal title
CANADIAN ENTOMOLOGIST
ISSN journal
0008-347X → ACNP
Volume
131
Issue
6
Year of publication
1999
Pages
779 - 786
Database
ISI
SICI code
0008-347X(199911/12)131:6<779:DIAOSI>2.0.ZU;2-Q
Abstract
A laboratory experiment was conducted to identify the overwintering stage o f the fir coneworm, Dioryctria abietivorella (Grote), in eastern Canada and determine the influence of photoperiod on diapause induction. In another e xperiment, different developmental stages were exposed to field conditions to evaluate their capacity to survive the overwintering period. Insects wer e either placed in the duff or exposed to ambient (above ground) conditions to assess the importance of overwintering site on winter survival. Exposur e of the fir coneworm to constant short-days or a daily decreasing photoper iod during larval development induced almost all insects to initiate diapau se at the fifth instar. Third-, fourth-, and fifth-instar larvae survived t he overwintering period when placed in the duff. Because the fir coneworm m ust leave its host tree and drop to the ground to avoid rigorous winter con ditions, we concluded that only fifth-instar larvae could resume developmen t in spring using such a strategy.